There are many applications in which it is desirable to dispense predetermined amounts of liquid into liquid containers. This is true, for example, in the food industry, wherein cans are often to be filled with food product or the like in liquid form and in a predetermined amount. One type of such substance, for example, comprises liquid butter fats to be added to food containers such as food cans in predetermined amounts.
In efficient mass production it is of course also desirable to dispense the liquid material as rapidly as possible, and in the case of production-line operations to dispense it fast enough to keep up with the desired speed of containers along the line.
One way in which liquid product might be dispensed into a container in a train of similar open-topped containers would be to advance the containers stepwise through stationary positions beneath a dispensing nozzle, and to turn each nozzle on sufficiently long to dispense the desired amount of liquid product while the container is stationary beneath it. Such starting and stopping of the line is undesirable, however, because in the long run it requires more time and more complicated equipment, and produces greater wear on the equipment and a certain amount of sloshing of the contents of the containers during abrupt starts and stops. Thus for many purposes such an approach is infeasible, or at least highly impractical.
Another approach is to allow the open-topped containers to move continuously at a relatively high speed in a sequential train beneath a liquid dispensing nozzle, and to turn on the nozzle as each can or container passes beneath it. While such an arrangement is feasible for many purposes, it does suffer from the drawback that, to avoid wastage or spillage of the liquid material, the maximum time interval during which the liquid can be dispensed is the time required for the container to move by a distance equal to the diameter of its top opening, and since the stream being dispensed will normally have an appreciable width along the direction or motion of the container, the permissible time interval for dispensing is even somewhat shorter than that. As the speed of the container increases, for example to speeds on the order of 600 containers per minute, or 10 a second, the times available for dispensing would typically be less than 1/20 of a second for each container, and it will therefore readily be appreciated that it is often difficult to provide squirts of liquid of the desired volume in such short time periods.
It is also desirable to inhibit the dispensing of the liquid should a container, on occasion, be missing from its expected position in the train of containers.
Accordingly, it is an object of the present invention to provide a method and apparatus for the high speed dispensing of liquids.
Another object is to provide such high-speed dispensing at accurately controlled times, and for accurately controlled time intervals, in predetermined amounts.
Another object is to provide apparatus suitable for such purposes which is relatively inexpensive to provide and operate, clean and easy to maintain, and relatively compact in structure.
A further object is to provide such method and apparatus which are capable of dispensing desired quantities of liquid through the open tops of containers continuously moving at a high rate of speed adjacent the dispensing unit.
Still another object is to provide the latter method and apparatus which are capable of dispensing a greater amount of liquid into an open-topped container for a given speed of the container past the dispenser than has heretofore been possible.
It is also an object to assure that the liquid is not dispensed when no container is in position to receive it.